Dwingelderveld is a nature reserve in the north-eastern Dutch province of Drenthe. It is part of the Natura 2000 network, and is the largest remaining continuous wet heathland in western Europe. In 1991, the Dwingelderveld was proclaimed a National Park by the Dutch government. The park covers some 3 800 ha and is protected under both the EU Birds and Habitats Directives. The area contains expansive areas of moist heath, fen-bogs, acid fens, active raised bogs, dry heath, drift sands and juniper shrubs. The various habitats are important for numerous bird species, including Bewick’s swan (Cygnus columbianus bewickii), black woodpecker (Dryocopus martius), little grebe (Tachybaptus ruficollis), whinchat (Saxicola rubetra), woodlark (Lullula arborea), and species of shoveller and wheatear; and also northern crested newt (Triturus cristatus). A former agricultural enclave, Noordenveld, is located at the heart of the National Park. Here, groundwater levels have been kept artificially low to benefit agriculture, resulting in dehydration and acidification of the heathland. In addition, the Noordenveld top soil is very rich in phosphates as a result of fertilisation for agricultural purposes. Dehydration, acidification and eutrophication are serious threats to the many vulnerable habitat types within the National Park.

Objectives

The objective of the “Healthy Heath” project was to restore the natural water balance over 1 100 ha of Dwingelderveld National Park, and to transform the former agricultural enclave Noordenveld back into heathland habitats. Specific project aims were to combat dehydration, eutrophication and acidification; enlarge the area of moist heath within the Natura 2000 network area; improve the quality of acid fens, active and recovering raised bogs, depression vegetation, and species-rich grasslands; and reduce disruption to the animals and birds characteristic of the area.

Results

“Healthy Heath” restored two agricultural enclaves, and conducted habitat restoration over a total area of 285 ha, to enlarge and defragment an area of wet and dry heathland in the Dwingelderveld Natura 2000 network site in the Netherlands. Heath restoration was based around two main actions: i) excavating top soil from the former agricultural enclaves to remove the high nutrient content of the soil caused by farming practices, and ii) reinstating the original hydrology.

The project team removed top soil to an average depth of 34 cm (10-50cm), but left any peat layers they encountered. Soil was removed over 174 ha at the Noordenveld enclave and over 15 ha at the Anserveld enclave, and also over a total area of 15 ha for the purposes of constructing an ecoduct that creates wet and dry corridors for wildlife. The excavated soil was used on site to construct a noise barrier alongside a road, to reduce the cost of soil removal and to reduce the impacts of vehicle noise on birds and animals. Creating the noise barriers also involved the cutting of surrounding vegetation and the planting of trees.

At Anserveld, 16 ha of encroaching forest was removed to set back the succession stage. A total of 11.4 ha of vegetation was removed at Noordenveld, but mainly to allow machines to start the soil excavation. Once nutrient-rich soils had been removed from the two former agricultural enclaves, heath clippings and sods were placed on the exposed ground to stimulate the development of heathland habitats. Sods were taken from an established heathland area of 1 ha to 'inoculate' the newly-exposed soil in the two enclaves. The project team experimented with different approaches for heathland development after excavation, to demonstrate best practices that can be replicated in other areas.

The project reinstated the original hydrology of the agricultural enclaves through several actions to facilitate the restoration of heathland habitats, including blocking a series of drainage ditches and channels to raise water levels. In total, the project team filled in 25.7 km of drainage ditches. The project created four new ponds, enlarged six ponds and reintegrated two more. The ponds and the ecoduct are encouraging amphibians and reptiles into the restored areas.

Reinstating the original hydrology was done so that water flows and water levels were obtained on different gradients, to favour a mosaic of rare heath habitats that are sensitive to hydrology change. The combination of soil removal and hydrological renovation has led to a higher coverage of dry and moist heath, depression vegetation, acid oligotrophic ponds and species-rich grasslands. In addition to habitat conservation and the protection of characteristic heathland species, the project’s work has beneficial effects in terms of flood prevention and climate change adaptation.

In terms of policy and legislation, the project directly implements the Habitats Directive, by improving the conservation status of target habitats, indirectly implements the Birds Directive, and addresses the first two targets of the EU Biodiversity Strategy (protecting species and habitats, and maintaining and restoring ecosystems). As a result of the restoration of the ecosystem services provided by wet heathland, such as the retention of water to prevent flooding, the project also helps achieve the objectives of the Floods Directive, the Water Framework Directive, and policy relating to climate change adaptation.

The project provided a strong demonstration of innovative heathland restoration that can be used as an example for similar restorations across the EU. In particular, the collaboration between Staatsbosbeheer, Natuurmonumenten and the relevant water board produced a clear win-win situation for both water storage and nature restoration, and the experimental monitoring enabled the testing and comparison of several treatment methods for heathland after excavation. Project outcomes were disseminated through extensive networking activities. Two seminars were organised (one for an international scientific audience and the other for nature managers in the Netherlands and Belgium).
“Healthy Heath” achieved several socio-economic benefits, such as the improved water retention capacity that helps prevent local flooding of farmlands and villages. The Dwingelderveld National Park is very important for the local economy, with hotels, campsites and restaurants dependent on the visitors it attracts. Through the project, the area was enlarged and the noise from the highway was reduced to the benefit of both wildlife and visitors. Also, the project’s communication activities publicised the National Park and its value, potentially attracting more visitors in the coming years.

Further information on the project can be found in the project's layman report and After-LIFE Communication Plan/After-LIFE Conservation Plan (see "Read more" section).

The Province of Drenthe is the regional government and is responsible for the implementation of nature and environmental policy in the province. The Dwingelderveld National Park is managed by a committee consisting of the provincial administration and landowners.